analyze.js

// there's got to be a better name for this function
const analyze = (xForms, data) => Object.keys(xForms).reduce(
  (acc, key) => Object.assign(acc, {[key]: xForms[key](data)}),
  {}
)

// it allows application of multiple transformations to a single value
// and combines the results of those transformations into a single object
const rectangleSideLengths = [3, 4]
const area = ([a, b]) => a * b
const diagonalLength = ([a, b]) => Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2))
const result = analyze({area, diagonalLength}, rectangleSideLengths)

console.log(result) // => {area: 12, diagonalLength: 5}

// I think it could be especially useful for manipulating objects received over
// APIs as they are sometimes not in the desired shape, contain superflous
// information, or require processing to derive useful values.
// I think it may be more elegant to do this by composing small
// transformations than to tackle the problem in a single function

combineTransformers.js

// I have no idea what to call this, but it separates transformations
// from the building up of a result so now we can combine our transformations
// to yield any sort of value we choose
const combineTransformers = (xForms, combiner, initialValue, data) => xForms
  .reduce((acc, xForm) => combiner(acc, xForm(data)), initialValue)

// Replicating the analyze example
const rectangleSideLengths = [3, 4]
const area = ([a, b]) => ({area: a * b})
const diagonalLength = ([a, b]) => ({
  diagonalLength: Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2))
})
const result = combineTransformers(
  [area, diagonalLength],
  Object.assign,
  {},
  rectangleSideLengths
)

console.log(result) // => {area: 12, diagonalLength: 5}